Objectives of the project are to study the deep cerebellar nuclei, the basal ganglia and the thalamic structures which receive the outputs from the cerebellum and the basal ganglia. The deep cerebellar nuclei and their relationship to the precerebellar nuclear inputs and to the cerebellar cortical inputs will be examined. In the basal ganglia project, we intend to study the extrinsic inputs (e.g., the substantia nigra, cerebral cortex and the central median), intrinsic neuronal organization and the projection cells of the caudate nucleus. The caudate influence on the substantia nigra and the globus pallidus will be examined. Neurotransmitters involved in this circuitry will be analyzed. A pattern of convergence of inputs from the cerebellum and the globus pallidus to the thalamic and the subthalamic structures will be examined. Anatomical technique utilizing horseradish peroxidase and electrophysiological technique (mainly intracellular analysis) will be employed. Cats will be used as experimental subjects.